Examining Brain‐Cognition Effects of Ginkgo Biloba Extract: Brain Activation in the Left Temporal and Left Prefrontal Cortex in an Object Working Memory Task

R B Silberstein,J Song,A Pipingas,P J Nathan,D A Camfield,C Stough

doi:10.1155/2011/164139

Abstract

Ginkgo Biloba extract (GBE) is increasingly used to alleviate symptoms of age related cognitive impairment, with preclinical evidence pointing to a pro-cholinergic effect. While a number of behavioral studies have reported improvements to working memory (WM) associated with GBE, electrophysiological studies of GBE have typically been limited to recordings during a resting state. The current study investigated the chronic effects of GBE on steady state visually evoked potential (SSVEP) topography in nineteen healthy middle-aged (50-61 year old) male participants whilst completing an object WM task. A randomized double-blind crossover design was employed in which participants were allocated to receive 14 days GBE and 14 days placebo in random order. For both groups, SSVEP was recorded from 64 scalp electrode sites during the completion of an object WM task both pre- and 14 days post-treatment. GBE was found to improve behavioural performance on the WM task. GBE was also found to increase the SSVEP amplitude at occipital and frontal sites and increase SSVEP latency at left temporal and left frontal sites during the hold component of the WM task. These SSVEP changes associated with GBE may represent more efficient processing during WM task completion.

Highlights

Ginkgo biloba extract (GBE) from dried leaves of the tree Ginkgo biloba is increasingly used in Europe and the United States of America to alleviate symptoms associated with age-related cognitive impairment such as age-related amnesic condition, vascular dementia and dementia of the Alzheimer’s type [1,2,3,4,5,6]
If GBE effects are mediated by cholinergic processes and the effects are similar to those of physostigmine as reported by Furey and colleagues [34, 35], it would be expected that the effects of chronic GBE treatment in an object working memory (WM) task will be to increase state visually evoked potential (SSVEP) latency at temporal and prefrontal sites
We observed an increase in accuracy from 71.7% in the postplacebo condition to 76.8% in the post-GBE condition

Summary

Introduction

Ginkgo biloba extract (GBE) from dried leaves of the tree Ginkgo biloba is increasingly used in Europe (especially Germany) and the United States of America to alleviate symptoms associated with age-related cognitive impairment such as age-related amnesic condition, vascular dementia and dementia of the Alzheimer’s type [1,2,3,4,5,6]. There have been a number of studies to investigate the effects of GBE supplementation on brain activity; the majority of these have only examined the effects of GBE on EEG frequency during a resting state. In relation to the chronic effects of GBE on EEG frequency, Hofferberth [42] reported a significant reduction in theta waveband activity associated with 3 months GBE at 240 mg/day in elderly patients with AD. If GBE effects are mediated by cholinergic processes and the effects are similar to those of physostigmine as reported by Furey and colleagues [34, 35], it would be expected that the effects of chronic GBE treatment in an object WM task will be to increase SSVEP latency (corresponding to reduced excitation or increased inhibition) at temporal and prefrontal sites. In relation to the behavioural effects of GBE, we hypothesized that there would be a significant improvement in both the speed and accuracy of performance in an object WM task following chronic GBE treatment

Methods

Results and Discussion

Brain Electrical Activity